THE TRANSMISSION OF VERTICAL WHOLE-BODY VIBRATION TO THE BODY SEGMENTS OF STANDING SUBJECTS

The effects of body postures in standing position on the transmission of whole-body vibration to body segments have been investigated. The m agnitude acceleration in the 2-axis direction of six body segments: th e metatarsus, ankle, knee, hip, shoulder and head has been measured du ring exposure to random vibration. Ten male subjects exposed to floor vibration stood in ten postures described as: relaxed standing, legs s tiffened, legs bent, standing on the toes, standing on one leg with or without support of the other foot and standing in steps. The transmis sibility of random vibration from the floor to the body points was cal culated at frequencies ranging from 4-250 Hz in 1/3 octave bands. The body postures of the subjects modified both the width of the resonant bands and the transmissibility values. The squared multiple correlatio n coefficient (R-2) between the transmissibility and the 16 variables (10 postures, 6 body segments) was not very high at resonance frequenc ies in the range 4-12.5 Hz but above 25 Hz, 50% of the variability in the transmissibility was due to the postures and the body segments. (C ) 1998 Academic Press.